8 BULLETIN OF THE 



Length of chela 5.0 mm. 



Breadth of " 1.7 



Length of its dactyliis 2.8 



" first ambulatory leg 9.0 



" dactylus 2.0 



" second ambulatory leg 11.6 



" dactylus 3.2 



" telson 2.5 



Breadth of " 4.8 



ANOMURA. 



LITHODIDEA. 



Lithodes Agassizii, sp. nor. 



Plate I. 



This species is allied to L. maia and L. antarctica in having no scale and 

 only a single spine at the base of the antenna, and in the general form and 

 armament of the carapax and appendages, but differs from them both con- 

 spicuously in the rostrum, which is rather short and tridentate, with the lateral 

 spines nearly as long as the rostral spine itself. The spines upon the carapax 

 and appendages are more numerous and much more acute than in L. maia, and 

 the marginal spines of the carapax are not very much larger than the dorsal. 

 There are only two adults, both females, in the collection, and these differ 

 remarkably from each other, and from three very young specimens, in the 

 number and length of the spines upon the carapax and legs. 



In the larger specimen the carapax, excluding the rostrum and spines, is 

 about nine tenths as broad as long, with a conspicuous sinus in the middle of 

 the posterior margin. The rostrum is very short, with an acute central spine 

 scarcely as long as the eye-stalks and with a somewhat shorter lateral spine 

 arising either side its base and directed upward and outward. The gastric 

 region is swollen and very high, separated from the cardiac by a very deep 

 depression, and armed with a pair of small spines just back of the lateral 

 spines of the rostrum, and back of these on the highest part of the region with 

 two widely separated pairs of much larger spines, while either side there is a 

 small spine opposite the large hepatic spine, between which and the obtusely 

 spiniform external angle of the orbit there are two spinigerous angular promi- 

 nences in the antero-lateral margin. There is a distinct notch in the antero- 

 lateral margin at the cervical suture, but back of this the margin is regularly 

 arcuate to the middle of the posterior margin, and is armed with about thirteen 

 stout spines, of which the larger are about as large as the hepatic spines. The 

 branchial region is considerably convex, and armed, in addition to those upon 

 the margin, with about ten large spines, between which there are a consider- 



